Smoke suppressing system for use with machine tools



Sept. 6, 1955 R. J. 5. PIGOTT 2,?16,9l4

SMOKE SUPPRESSING SYSTEM FOR USE WITH MACHINE TOOLS Filed Feb. 20, 1952 INVENTOR. R.J- s. p eo'r'r Is ATTORNEY United States Patent SMOKE SUPPRESSING SYSTEM FOR USE WITH MACHINE TOOLS Reginald J. S. Pigott, Pittsburgh, Pa., assignor to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware Application February 20, 1952, Serial No. 272,670

2 Claims. (CI. 82-34) This invention relates to a smoke suppressing system for use with machine tools. More particularly, the system is an accessory for lathes and the like, which comprises shower heads disposed above and preferably also beneath the cutting tool, receiving liquid from a connected source of supply and discharging it in an annular curtain which impinges upon the tool and work, and which envelops the region of the cut, so that smoke, vapors and fumes, as formed, are confined and immediately absorbed.

High heat is generated in the cutting and shaping of metals. In a lathe, for example, the tool engages the work under a pressure of the order of 50,000 pounds per square inch and the continuously removed chip rubs heavily on the surface of the tool. For many years it has been conventional practice to flow a solid, heavy stream of oil or other liquid coolant over the chip and tool shank in order to reduce their temperature. While this has been partly effective it does not serve to absorb the smoke which is produced on contact of the oil with the heated metal and where the smoke is excessive hoods, ducts and washers have been resorted to for alleviation of the nuisance.

In accordance with my invention disclosed in application Serial No. 228,843, which resulted from the discovery that oil flowing downwardly over the chip does not appreciably cool the highly heated tool or afford adequate lubrication of its cutting edge, a new system of applying cutting oil is provided wherein a small high speed jet of cutting fluid is projected from beneath the tool into the clearance space between the tool and work. The oil so placed vaporizes adjacent the highly heated cutting edge of the tool and passes as vapor through the microscopic clearances between the tool and work, to condense therebeyond and lubricate the edge and under surface of the chip. Tool life which previously had been limited in many cases to a matter of minutes has been increased by this new system 300 to 1200 per cent. But since the oil now reaches the hotest portion of the tool, close to the edge, more smoke is ordinarily formed than in the conventional practice wherein the highly heated cutting edge is shielded from contact with any appreciable amount of oil by the overlying chip. Thus, my present invention is not merely designed to suppress the smoke formed in cutting by conventional methods, but is also particularly desirable for use in the new method of applying cutting liquids described and claimed in my aforesaid copending application.

It is accordingly an achieved object of the invention to provide a smoke suppressing system which is compact, readily installed upon the machine and inexpensive as compared to installations employing hoods, ducts, washers, etc.

A further object of the invention is to provide a smoke and fumes suppressing system for use with machine tools in which an enveloping curtain of fluid surrounds and completely encloses the region of cut so as to confine and 2,716,914 v Patented Sept. 6, 1955 2 absorb the smoke and fumesproduced in a cutting operation.

Other and further objects and advantages of the invention will be apparent from the following description and drawings, in which Figure 1 is a side view, partly in vertical section, showing the system as utilized in a turning operation on a lathe.

Figure 2 is a plan view of the lower shower head, taken along line 22 of Figure 1, with the work piece shown in broken lines.

Referring more particularly to the drawings, a rotating work piece 10 is shown being turned down to smaller diameter by a tool 11 which is clamped in tool holder 12 and which in its cutting action continuously removes a chip 13 from the work piece. Mounted adjacent the work piece, and desirably mounted on the carriageof the machine (not shown), so that it will move with the tool, there is a fixture comprising an upper distributor or shower head 14 and a lower distributor or shower head 15 connected by pipes 16 and 17 to a T-fitting 18 which communicates through pipe 19 with a source of fluid coolant. While oil is preferred as a coolant, the use of water or other liquid or gaseous medium capable of absorbing smoke and fumes is within the purview of this invention. Solely for purposes of description, however, liquid 'is specified as the fluid used.

Valves 20 and 21 control flow of the liquid in the branch pipes 16 and 17. The upper distributor 14 which overlies the cutting area comprises a dished body 22 with a covering face plate 23 which is formed with two circuas shown more particularly in Figure 2.

Where the installation includes a small, high speed jet directed upwardly from beneath the tool a. nozzle 32 is mounted to project through the curtain of spray discharged from the orifices 31 in the lower shower head, which nozzle discharges a fine, thin jet of liquid 33 into the clearance between the tool and the work, as shown in Figure 1. The lateral spray through which the nozzle 32 projects forms an effective smoke-impenetrable wall which forms the bottom of the liquid envelope surrounding the tool and work.

Liquid discharged from the upper shower head 14 flows downwardly in an annular, dense curtain which is impenetrable to smoke and fumes by reason of the fact that the orifices of the outer concentric series are closely spaced and in staggered relation. The annular curtain of liquid so discharged from the upper shower head has a tendency to spatter as it impinges upon the work, and in order to prevent escape of smoke and fumes due to this disruption of the curtain the lower shower head discharges directs a heavy, solid stream of liquid downwardly over the chip and tool shank while the staggered series of orifices 26 and 27 direct additional sprays of liquid to the region of cut, to assist in the cooling action.

Since smoke which is formed in a cutting operation emerges principally from beneath the tool and rises around the work piece the enclosed chamber which is produced by the surrounding liquid wall not only serves to confine the smoke but to absorb it and wash it away as the liquid drains to an underlying sump from which it may be pumped and recirculated.

While it will be understood that my invention is not restricted in its applicability to a system employing a thin high-speed jet of cutting fluid, since it is equally desirable to suppress smoke where the older conventional methods of applying cutting fluid are employed, it will be apparent that this invention provides a simple and effective means of suppressing smoke which avoids the use oi. elaborate and costly accessory equipment such as hoods, blowers, ducts, washers, and the like.

It is also to be understood that wherever the word smoke is used in a general sense in the foregoing specification and in the claims it is intended to include within its meaning vapors and fumes which are produced in the metal working operation.

What I claim as my invention is:

l. A metal cutting machine comprising a Work piece support, a cutting tool for traversing a work piece held in the support, a source of liquid supply, an upper liquid distributor positioned above the area where the tool engages the work and connected by piping to said source of supply, said upper distributor comprising an enlarged head having a face plate formed with a central opening overlying the point of cut and small, closely spaced orifices adjacent its periphery, whereby a heavy stream of liquid discharges through said central opening onto the chip formed in cutting and a spaced, surrounding liquid curtain is formed by the plurality of jets discharged from the peripheral orifices which encloses a space about the point of cut and thereabove, a lower liquid distributor positioned below the area where the tool engages the work and connected by piping to said source of supply, said lower distributor comprising an annular conduit formed with a series of closely spaced orifices directed upwardly toward the work and having in its inner annular wall a series of orifices discharging radially inward, whereby an enveloping curtain of spray will be discharged upwardly to merge with the descending spray from above, the liquid-walled chamber so formed by the upper and lower spray jets being closed at its bottom by the radially directed jets, whereby smoke produced in the cutting opcration will be confined and absorbed by contact with the liquid sprays and chips from the cutting operation are removable at bottom without disruption of the seal provided by the radial jets.

2. A metal working machine comprising a work support, a cutting tool for traversing a work piece held in the support, a liquid distributor mounted to overlie the work piece in the region of its engagement by the tool, said distributor comprising a hollow cup-shaped body connected to a source of liquid supply and a face plate formed with a central orifice in vertical alignment with the point of cut and further formed with concentrically spaced orifice means for directing liquid in a downwardly flowing curtain impinging upon the work piece and tool in engagement therewith, a second distributor connected to said source of liquid supply and comprising a hollow ring formed with annular orifice means for discharging a curtain of liquid upwardly against the work piece and tool, and being further formed with orifice means in its inner annular wall for discharging liquid transversely of the ring, thereby to produce a smoke impenetrable liquid curtain which extends around the section of work piece being cut and which is boxed in at bottom without impediment to the washing away of removed chips.

References Cited in the file of this patent UNITED STATES PATENTS 943,422 Knoepfel Dec. 14, 1909 1,100,845 Richter June 23, 1914 1,611,028 Harrison Dec. 14, 1926 1,657,375 Dinardo Jan. 24, 1928 2,434,679 Wagner Jan. 20, 1948 FOREIGN PATENTS 208,032 Switzerland Dec. 31, 1939 

